Homeopathy/PreviousVersion

Template:TOC-right Homeopathy or homoeopathy is a system of alternative medicine. The term derives from the Greek hómoios (similar) and páthos (suffering). The underlying concept of homeopathy is "like cures like"—a principle described by Hippocrates more than 2,000 years ago that has been used in various medical systems since then in many diverse cultures. "Like cures like", the "Law of similars", and related maxims are common in anthropological literature.

Homeopathy is based on "the principle of similars", which asserts that substances known to cause particular symptoms can also, in low and specially prepared doses, help to cure diseases that cause similar symptoms. Although homeopathy is practiced by some medical doctors, as well as by other health professionals in virtually every country in the world, most mainstream medical doctors and scientists, particularly those in the West, do not accept the principles of homeopathy today. In addition to the professional practice of homeopathy, consumers all over the world use homeopathic medicines for self-treatment for common self-limiting ailments and injuries.

Some of these principles of homeopathy have been utilized in various forms for thousands of years, but they were first methodically set out by a German physician, Samuel Hahnemann (1755–1843), who observed that a medicine sometimes evoked symptoms similar to those of the illness for which it was prescribed. In homeopathic theory, every person has a "vital force", with the power to promote healing and/or maintain good health (the term "vital force" is akin to qi in traditional Chinese medicine). In this theory, the symptoms of a disease reflect efforts of the vital force to counter infection, or to resist damage from environmental toxins or from various stresses. Homeopathic treatment attempts to strengthen this "vital force" with the help of remedies, which are extremely small doses of drugs diluted in water or ethanol and dispensed in pills or liquid form. Remedies are chosen for their ability (in large doses) to provoke the very symptoms that the remedy is intended to heal (and thereby for their presumed ability to stimulate natural healing). Homeopaths believe that this "vital force" is akin to what physiologists would call the body's "defense systems".

"Classical homeopathy" refers to the original principles in which remedies are chosen according to the physical, emotional, and mental symptoms that the sick individual is experiencing, rather than only the diagnosis of a disease. "Commercial" or "user-friendly" homeopathy refers to the use of a mixture of remedies in a single formula, generally chosen for their ability (in large doses) to produce symptoms of a specific disease.

Historical origins

The early Greek physician Hippocrates of Cos (c. 450 BCE - 380 BCE) was a medical historian who is considered to be the "father of medicine". He wrote about many healing practices, one of which relied upon the use of "like to cure like." In the 15th century, the alchemist, physician and astrologer Paracelsus asserted the healing power of "signatures", meaning that the appearance of a substance in nature (its color and its shape), represented the types of diseases which it could cure. However, it was not until the late 18th century that this principle was coupled with an experimental method to determine in detail what symptoms a substance causes and therefore determine what a medicine can cure. This experimental method was developed by the German physician, Christian Friedrich Samuel Hahnemann (the method of "provings" - studies of the effects, in humans, of high dosages).

After 1783, disillusioned with the medicine of the time and the many toxic effects of its treatments, Hahnemann gave up his medical practice and devoted himself to translating medical books (he knew nine languages), including many of the leading textbooks of the day. One of these was the Treatise on Materia Medica (1789) by William Cullen, the leading physician of the 18th century; Cullen had written that cinchona bark (which contains quinine) was effective in treating malaria because of its bitter and astringent properties. Hahnemann questioned this, because he knew that other substances were as bitter and astringent, but had no therapeutic value in this deadly disease.

Being an avid experimenter, Hahnemann took cinchona bark himself and saw that the symptoms that it caused were similar to the symptoms of the diseases for which it was prescribed. He then experimented with other substances, and found that the symptoms that they caused were also similar to the symptoms of the diseases for which they were prescribed. These experiments led him to formulate the "Principle of Similars" - similia similibus curentur or "let likes cure likes". He used this to develop a new system of health care, as an alternative to the often toxic and ineffective drugs and treatments offered by conventional physicians of the time.

Hahnemann named his system of health care "homeopathy" (meaning "like disease") and coined the term "allopathy" ("different than disease") to refer to the conventional medicine of the day, because its drugs were sometimes "similar," sometimes "opposite," but usually just "different" to the symptoms of the sick person.

For the first two decades of Hahnemann's practise of homeopathy, he used "crude" doses of various medicinal substances ("crude", in homeopathic use, means doses that still contain some of the original ingredient). He strove to find the lowest doses at which his remedies would still be effective, as he thought this the best way to avoid any adverse side-effects. To his surprise, it seemed that reducing the dose did not reduce the effectiveness of his treatments. Instead, he concluded that his remedies worked better the more he diluted them as long as he “potentized” them between each stage of dilution by vigorous shaking (succussion). Homeopathy thus became inextricably linked with this process of ultradilution – repeated dilution of substances by succussion. Although Hahnemann was an avid experimenter, he did not offer a clear explanation as to how or why these potentized medicines might have therapeutic benefits; Hahnemann distrusted all theoretical explanations, and argued that all that mattered was whether a treatment was therapeutically effective.. He believed that diseases were caused by "spirit-like derangements of the spirit-like power that animates the human body", and that effective healing called for medicines that would stimulate this force.

Homeopathy was introduced into the U.S.A. in 1825 by Hans Burch Gram, a Boston-born doctor who had studied homeopathy in Europe. In 1830, the first homeopathic schools opened (the first homeopathic medical college in the U.S.A. opened in 1835, in Allentown, Pennsylvania), and throughout the 19th century dozens of homeopathic institutions appeared in Europe and the U.S.A. Apart from his ventures into homeopathy, Hahnemann had been a prominent and respected public health reformer, and the Medical Society of the Country of New York had given him honorary membership. However, a few years later the society rescinded this when they realized the "ideological and financial threat" that homeopathic medicine posed. In 1844, the first U.S. national medical association - the American Institute of Homoeopathy - was established. By the end of the 19th century, 8% of American medical practitioners were homeopaths, and there were 20 homeopathic medical colleges (including Boston University, New York Medical College, and the Universities of Ohio State, Iowa, Minnesota and Michigan) and more than 100 homeopathic hospitals in the U.S.A. One reason for the growing popularity of homeopathy was its relative success in treating people suffering from the infectious disease epidemics that raged at the time. Cholera, scarlet fever, typhoid fever, and yellow fever were rampant and killed many people, but death rates in homeopathic hospitals were often very much lower than in the conventional hospitals, whose cures – purging, blood-letting and mercury treatments, were often worse than the diseases, and did nothing to combat them.

However, in the early 20th century, the "Flexner Report," sponsored by the Carnegie Foundation with support from the American Medical Association, triggered major changes in American medical education. As a result, most homeopathic schools were closed down, while others became conventional medical schools (including Boston University, New York Medical College, and Ohio State University). In the 1960s, the popularity of homeopathy began to revive again in the U.S.A, and a 1999 survey reported that over 6 million Americans had used homeopathy in the previous 12 months.

Homeopathic "provings"

Homeopathic practitioners derive their remedies from provings, in which volunteers are given substances (usually in single-blind or double-blind trials), the effects of which are recorded in textbooks, called Materia Medica and Repertory, or nowadays in expert system software. Homeopathic provings provide an experimental basis to determine what a substance causes in overdose and thereby what it is thought to cure. The symptom complexes that these substances cause are subsequently used to compare with a patient's physical and psychological symptoms in order to select, as the appropriate most similar remedy, the substance whose effects are closest to the patient's symptoms—called the "similimum".

An example of a proving is that of Bambusa arundinacea (bamboo). In this proving, the 20 subjects did not know whether they were taking the bamboo or a placebo, and the investigator knew only the substance name, but not, at that time, its properties. The 6C and 30C potencies were used, and the investigators found that the central idea of this new remedy is the “search for support”. The symptoms elicited by the treatments are detailed in a 237-page book, which details the hundreds of symptoms that bamboo was found to cause (and therefore, accord to homeopathic principles, potentized doses of this medicine will stimulate to heal people whose symptoms are similar to this syndrome of symptoms).

In the first two phases of the proving, all of the subjects were given the remedy in various potencies. In the third phase, seven of them were given placebo. The study started in October 1994 and lasted until February 1995, during which time they recorded every symptom they experienced in a diary and noted whether it was a persistent, new, old, altered or unusual symptom. The recorded symptoms take up 84 pages in the book. The symptoms are then converted into repertory rubrics in the next 46 pages. The last 76 pages consist of the author's commentary about the proving symptoms, and 14 cases in which bamboo was the prescribed remedy.

The recorded symptoms need to be interpreted by an experienced homeopath to understand the conditions for which the remedy might be considered as possibly useful. In the case of bamboo, following the theme of "search for support", the proving is cited as indicating the remedy's value in treating post-natal depression accompanied by irritability and impatience, for example when a mother makes statements like "I can't handle my child and I have no desire to get out of bed." In cases requiring physical support, it is indicated when there is a need for support in the back associated with pain, sciatica, stiffness and changes to the spine. Finally it is indicated with symptoms such as swelling of the breasts before menses accompanying depression.

In September 2006 the U.K.’s licensing body, the Medicine and Healthcare Products Regulatory Agency, altered their regulations to permit homeopathic remedies to be advertised using homeopathic provings to support their claims (justifying phrasing such as “For the relief of...”. This change elicited protests from scientists, who called it a departure from the principle that such claims should be justified by evidence of efficacy.

Homeopathic manufacture of remedies

In the U.S.A., the Homœopathic Pharmacopœia of the United States is a legally recognized handbook that describes how to manufacture homeopathic drugs. This reference is approved by the Food and Drug Administration (FDA), the governmental agency that regulates drugs, although having never been listed in the HPUS puts the homeopathic drug in a different standard of regulation than conventional drugs and medical devices. A summary describes the principles:

FDA regulates homeopathic drugs in several significantly different ways from other drugs. The Manufacturers of homeopathic drugs are deferred from submitting new drug applications to FDA. Their products are exempt from good manufacturing practice requirements related to expiration dating and from finished product testing for identity and strength. Homeopathic drugs in solid oral dosage form must have an imprint that identifies the manufacturer and which indicates that the drug is homeopathic.

In 1938, the federal Food, Drug, and Cosmetic Act, sponsored by New York Senator Royal Copeland, a homeopathic physician (and former homeopathic medical school dean) gave the FDA the power to regulate drugs, and gave legal recognition to the "Homeopathic Pharmacopeia of the United States" as a compendium of drugs. In contrast, non-homeopathic drugs for which a New Drug Application is required must be accompanied by approved evidence of safety and efficacy; simple listing in a reference is not sufficient. Today, homeopaths use about 3,000 different remedies, from animal, plant, mineral, or synthetic sources.

By convention, the first letter of the Latin-derived name of such preparations is capitalized. When the source is well-defined, the traditional name rather than chemical, International Nonproprietary Name or biological nomenclature, is preferred, such as Natrum muriaticum rather than sodium chloride. Most remedies used in homeopathy are derived from flowering plants, but some conifers and ferns are used, as well as fungi, including lichens, and brown and red algae. Other remedies are derived from the mineral and animal kingdoms. Ultimately, any substance can become a homeopathic medicine if "drug provings" (tests to determine the symptoms produced by high doses) are first conducted to determine what it causes in overdose and therefore what it can cure in potentized doses.

Homeopathic remedies are available in several different forms (single medicine, homeopathic formula or complex medicines, and a limited number of external applications). Remedies for internal consumption come either in pill form or as liquid. Most do not require a doctor's prescription, but some may need one if the dosage is in a non-potentized or low potency dose and if the substance is potentially toxic (in Europe, a medicine must be diluted at least 1:10 three times to be deemed homeopathic). In the U.S.A., if a homeopathic remedy is claimed to treat a serious disease such as cancer, it can be sold only by prescription. Only products sold for “self-limiting conditions”—colds, coughs, fever, headaches, and other minor health problems that are expected to go away on their own—can be sold without a prescription (over-the-counter).

Preparation of homeopathic remedies

The most characteristic — and controversial — principle of homeopathy is that the efficacy of a remedy can be enhanced and its side-effects reduced by a process known as 'dynamization' or 'potentization'. In this process, liquids are diluted (with water or ethanol) and shaken by ten hard strikes against an elastic body ('succussion'), to get the next, succeeding higher potency. For this, Hahnemann had a saddlemaker construct a wooden 'striking board', covered in leather on one side and stuffed with horsehair. When insoluble solids such as oyster shell are used for remedies, they are diluted by grinding them with lactose ('trituration'). The original serial dilutions by Hahnemann used a 1 part in 100 (centesimal; $'C'$ potencies), or 1 part in 50,000 ( Quintamillesimal; $'LM'or'L'$ potencies). Dr. Constantine Hering of Philadelphia, later introduced the Decimal potencies ('D' or 'X' potencies). A large number of homeopathic medicines sold in health food stores and pharmacies are "low potencies," that is, doses that are 3X, 3C, 6X, 6C, 12X, and 12C, all of which, except the last dose, has material doses of the original substances in the medicine. The higher potencies (30, 200, 1,000 and higher) are more commonly prescribed by professional homeopaths, and typically, homeopaths have found these doses to be powerful enough to only need a single dose to have a long-term effect (from several weeks to several months or longer). Research studies that determine the efficacy of homeopathic medicines are discussed elsewhere in this article.

The dilution factor at each stage is 1:100 ('C' potencies), 1:50,000 ('LM' potencies) or 1:10 ('D' or 'X' potencies) ; Hahnemann advocated $30C$ dilutions for most purposes (i.e. dilution by a factor of 100³⁰ = 10⁶⁰). The number of molecules in a given weight of a substance can be calculated by Avogadro's number (see below), and it is extremely unlikely that even one molecule of the original substance would be present in a $30C$ dilution. Thus, homeopathic remedies of a high 'potency' contain just water, but according to homeopaths, the structure of the water has been altered (see memory of water).

Similia similibus curentur : the law of similars

Similia similibus curentur or 'let likes cure likes', is the assertion that a disease/problem can be cured by remedies that (in macroscopic, milligram doses) produce the same symptoms as those of the disease. This assertion, known as "the law of similars", is a guiding principle in homeopathy. Homeopaths consider that two conventional concepts, vaccination, and hormesis, can be considered as analagous to homeopathy's law of similars and the use of small doses.

Mainstream scientists and medical doctors today do not think that the principle of similars is generally true or useful, and they explain the efficacy of vaccination without referrring to it. Physicians of the 19th century however did consider that the principle could be valuable. For example, Emil Adolph von Behring (1854-1917), who won the first Nobel Prize in medicine in 1901 for discoveries that led to vaccines against tetanus and diphtheria, and who some consider to be the father of immunology, asserted that vaccination is, in part, derived from the homeopathic principle of similars.

In spite of all scientific speculations and experiments regarding smallpox vaccination, Jenner’s discovery remained an erratic blocking medicine, till the biochemically thinking Pasteur, devoid of all medical classroom knowledge, traced the origin of this therapeutic block to a principle which cannot better be characterized than by Hahnemann’s word: homeopathic.

Although homeopathic remedies and vaccinations both use low doses of active ingedients, there are important differences. First, the doses used in homeopathic remedies are always very much lower than used in vaccines. Second, vaccines produce a measurable immune response (e.g., immunoglobulin production). Homeopathic remedies do not routinely produce a measurable immune response. Thus conventional treatments involve application of measurable doses of substances, at levels known to activate a cellular response. In contrast, homeopathic preparations above the $24X$ ($12C$) potencies do not contain enough molecules to activate any known metabolic or signalling pathway.

Mithridatization (which is not a term used in contemporary science or medicine) may be a better metaphor than vaccination for homeopathic treatment. Mithridatization is the chronic administration of subtoxic doses of a toxin, in an attempt to develop resistance (or "tolerance") to large doses of the toxin. It is said that Mithridates VI Eupator, King of Pontus (132-63 BC), used this technique to protect himself from his enemies.

There are many different mechanisms by which tolerance can develop - and exposure to repeated small doses does not always result in tolerance. A herpetologist who receives many small doses of snake venom may indeed become tolerant to them. A beekeeper, however, may become hypersensitive to the venom and, after receiving a sting, go into anaphylaxis. This type of response to small, not necessarily precisely measured, doses is not predictable on an individual basis. 'Allergic desensitization' is a technique used in conventional medicine to treat individuals who have a specific allergy to something that they cannot easily avoid. This involves exposing the patient repeatedly to tightly controlled doses, increasing the doses gradually over time. This treatment can be dangerous (exposure of sensitive individuals to an allergen can produce anaphylaxis), and it has very inconsistent efficacy, so is normally only attempted when the allergy poses serious restrictions on the patient's normal life.

Both mithridatization and homeopathy might be considered as instances of hormesis, which describes the phenomenon that some chemicals at high concentrations have opposite biological effects to those at low concentrations.

Professional homeopaths: who are they?

There are no universal standards for homeopathic education, so licensing and regulation varies from country to country and from state to state within the U.S.A. In some countries, all (or virtually all) professionals that use homeopathic treatments are MDs (such as France, Spain, Argentina, Colombia). Some countries have exclusively homeopathic medical schools (India, Pakistan, Mexico etc.), some have naturopathic medicine colleges in which students are taught homeopathy as part of their curriculum (Germany has its "heilpraktica"/health practitioners; the U.S.A., Canada, and Australia have naturopathic medicine schools that include homeopathy), and some certify "professional homeopaths" who have attended homeopathic schools and who then pass independent examinations that grant "certification" as homeopaths. In the U.S.A., MDs and DOs are eligible for this certification. There is also a separate certification process available only to MDs and DOs (there are similar choices of certification available in the U.K. for medical doctors, who've done at least MBBS).

In Europe, homeopathy is practiced by many conventional physicians, including 30-40% of French doctors and 20% of German doctors. Some homeopathic treatment is partly covered by some European public health services, including in France and Denmark. In the U.K., five homeopathic hospitals are funded by the NHS and homeopathic remedies are sold over the counter, and there, homeopathy is one of the most popular alternative and complementary treatment modalities . Of 248,000 registered practitioners of medicine in the U.K., about 400 are members of the Faculty of Homeopathy. However, homeopathy is still not a fully regulated profession in the U.K. - anyone can declare themselves to be a homeopath and practise without any qualification ("common law" that allows freedom of choice in medical care in England has a long history)

In France and Denmark, licenses are required to diagnose any illness or to dispense any product whose purpose is to treat illness. In many countries, however, there are no specific legal regulations concerning homeopathy. In Austria, the public health service generally requires proof of effectiveness to reimburse medical treatments, but makes an exception for homeopathy.

In India, where there are more than 200,000 registered practitioners of homeopathy, homeopathy is formally recognised by the Government as one of the Indian 'National Systems of Medicine', under the Department of AYUSH (Ayurveda, Yoga & Naturopathy, Unani, Siddha and Homeopathy), while conventional, western medical education is controlled by the Medical Council of India. About 10% of the Indian population depends solely on homeopathy for their health care needs. In India, it is illegal to practise as a homeopath without a license & professional qualifications.

Almost 70% of all over-the-counter homeopathic remedies are sold in Western Europe. France is the largest market for homeopathic remedies in the world, worth over 300 million euros in 2003 (in a total over-the-counter drug market of over 770 billion euros), followed by Germany (200 million euros). The global self-medication market is estimated at 48.2 billion dollar (13.4% of the world pharmaceuticals market), of which sales of homeopathic remedies account for 0.3%.

A typical homeopathic visit

When a homeopath is conducting an interview to characterise a patient's syndrome of symptoms, some "categories of change" are identified as important: (1) emotion (2) mentation (3) specific physical functioning (4) general physical changes (5) perception of self (6) relationships (7) spirituality (8) lifestyle (9) energy (10) dream content and tone (11) well-being (12) perceptions by others (13) life relationships (14) a sense of freedom or feeling less 'stuck' (15) sleep (16) coping (17) ability to adapt (18) creativity (19) recall of past experiences

Homeopathic remedies can be prescribed by pure homeopaths, naturopaths, acupuncturists, chiropractors, and mainstream physicians with additional homeopathic training and certification, and how these decide what to prescribe will differ accordingly. Classical homeopaths place emphasis on the patient's symptoms and their psychological state, and they gather this information from an interview, typically lasting from 15 minutes to two hours, with one or more follow-up consultations of five to 45 minutes. Consultations of these lengths are comparable to conventional physicians using their clinical judgment, rather than shorter visits demanded by third-party economic constraints. They place more emphasis on the way the patient experiences their disease rather than only diagnosing the disease - i.e. they give priority to the syndrome of symptoms rather than to the results of conventional medical tests alone. A diagnosis will also be used to rule out treatment with unnecessary remedies. This differs from the conventional medical approach, which is to try to identify the causes of the disease.

After the interview, the homeopath consults the references described in the table on the right. Some homeopaths make quick prescriptions based on "keynotes" -the highlights of the best known characteristics of a remedy, but the real challenge of homeopathic practice is to find the remedy that best matches the patient's symptoms - the "similimum". A fundamental reasons for conflict between conventional medicine and homeopathy is that homeopathy rejects the concept of treatments that target mechanisms of disease, and instead uses remedies that target syndromes of symptoms.

• A physician qualified in both homeopathy and conventional medicine, after diagnosing a chronic condition that does not have consistently effective conventional treatments, may prescribe a homeopathic remedy which he feels may be more effective and is likely to have fewer side effects than conventional drugs.
• Homeopaths recognize that trauma might require conventional medical attention, but may complement the conventional treatment with homeopathy.
• Homeopaths disagree with conventional medicine about the role of immunization and chemoprophylaxis for infectious diseases.
• Homeopathic practitioners prescribe remedies for many conditions. For some conditions, like asthma and acute bronchitis, remedies are often prescribed not only to alleviate chronic symptoms, but also to treat acute attacks. Homeopathic remedies might also be used after an asthmatic episode with the intent to prevent recurrences.
• An adequately trained homeopath is expected to recognize symptoms that indicate an acute and potentially fatal condition. The practitioner is expected to have emergency medical training and equipment appropriate to his or her level of training in the place of practice (e.g., dressings and basic airway management tools for an individual with training at the Emergency Medical Technician (EMT) of Basic or higher level, and preferably an automatic external defibrillator and advanced cardiac life support resources generally accepted as appropriate for an office. Potentially serious acute ailments may require medical supervision, but homeopaths sometimes prescribe remedies either for adjunctive use or as alternatives to conventional treatment.

The homeopathic treatment of acute ailments or injuries does not need the same depth or breadth of interview as constitutional treatment. According to homeopaths, because the symptoms of a common cold or a headache or an allergy vary from person to person, each will need a different remedy. However, they believe that people who experience an injury generally have similar symptoms, so they think that some homeopathic remedies might be routinely useful in such cases.

Homeopaths who practice "classical homeopathy" prescribe just one remedy at a time - a remedy that best fits the patient. The same remedy might thus be prescribed for patients suffering from very different diseases, conversely patients suffering from what would be diagnosed conventionally as the same disease may be prescribed different remedies. For example, for gangrene, homeopathic remedies are prescribed to strengthen a person's own defenses and to initiate healing. Some homeopathic medicines for gangrene may include Arsenicum Album, Secale (from rye/ergot), and Carbo vegetabilis (from charcoal), amongst many others.

The claims for homeopathy

Homeopaths view illness as a systemic condition, a disturbance in the overall homeostasis of the total being and accordingly, consider that almost any sick person, may benefit from proper homeopathic treatment. "The physician must remember that he is treating a patient who has some disorder; he is not prescribing for a disease entity." .

Homeopathic practitioners claim that their remedies are useful for a wide range of minor ailments, from cuts and bruises to coughs and colds. Patients often come to homeopaths with long-term problems which have not responded to conventional medicine, and homeopaths prescribe remedies to people with these conditions. Some of the common ailments for which patients seek homeopathic care are eczema, chronic fatigue syndrome, asthma, migraine, irritable bowel syndrome, allergic disorders, arthritis, fibromyalgia, hypertension, Crohn's disease, premenstrual syndrome, rhinitis, anxiety and depression. They also treat patients with the most serious diseases, including multiple sclerosis, chronic obstructive pulmonary disease, and cancer. and AIDS

Homeopaths claim that there is objective evidence that some of their treatments are beneficial (see Tests of the efficacy of homeopathy), and they believe that the success of homeopathy for the last 200 years is itself an indication of its value.

Conflict with conventional medicine

James Tyler Kent and homeoprophylaxis Some homeopaths also believe that their treatments can prevent disease, a notion known as "'homeoprophylaxis". James Tyler Kent (1849-1916) was prominently associated with the spread of homeopathy in the U.S.A., and much modern practise of homeopathy is based on his repertory, published in 1897. Kent denied the conventional germ theory of infectious disease, declaring that "The microbe is not the cause of disease. We should not be carried away by these idle allopathic dreams and vain imaginations but should correct the Élan vital". Instead, he believed that illness had spiritual causes: "You cannot divorce medicine and theology. Man exists all the way down from his innermost spiritual, to his outermost natural." Kent promoted the idea that homeopathic remedies could not only cure diseases, but also prevent them: "The great prophylactic is the homeopathic remedy. After working in an epidemic for a few weeks, you will find perhaps that half a dozen remedies are daily indicated and one in these remedies in a larger number of cases than any other. This one remedy seems to be the best suited to the general nature of the sickness. Now you will find that for prophylaxis there is required a less degree of similitude than is necessary for curing. A remedy will not have to be so similar to prevent disease as to cure it, and these remedies in daily use will enable you to prevent a large number of people from becoming sick. We must look to homeopathy for our protection as well as for our cure". The notion of homeoprophylaxis has not received any support from systematic trials and has no place in conventional medicine. Suggestions that homeopathic treatments are an effective alternative to vaccination are regarded as irresponsible by many public health professionals, and also by some professional homeopathic organizations; in the U.K., The Faculty for Homeopathy recognizes the importance of childhood vaccination and does not support the common use of homeopathic remedies in place of conventional travel vaccinations and for malaria prevention, warning travellers "that there is no evidence that these provide any degree of protection."

The theory underlying homeopathy is not considered plausible by most scientists working in academic institutions in Europe and the U.S.A., and in key respects, the treatment advice offered by homeopaths is in disagreement with conventional medicine.

The conventional view is that homeopathy, insofar as it has any effect at all, exploits the placebo effect - i.e. that the only benefits are those induced by the power of suggestion, by arousing hope, and by alleviating anxiety. Conventional medical opinion does not deny the efficacy of placebo treatments in many cases, and placebos have played a large part in conventional medicine since their first deliberate use by William Cullen in the 18th century. Many modern physicians, however, consider it unethical to deliberately mislead their patients; rather than prescribing placebos themselves, some therefore prefer to refer patients to regulated practitioners of alternative medicine.

There is however concern among mainstream practitioners that some patients seek homeopathic treatment as a first resort, even for conditions where there are treatments that the mainstream considers effective. For example, asthma and other respiratory disorders with a seemingly mild initial presentation can be a life-threatening condition, and acute attacks, if not treated effectively, can lead to sudden death. According to conventional opinion, prescribing homeopathic remedies in these cases may delay the delivery of conventional treatment, considered likely to be effective by mainstream physicians, with potentially serious consequences. Medical organisations advise that there is no evidence that homeopathic remedies are effective in these circumstances, and recommend that they should only ever be used in conjunction with conventional treatment.

Homeopaths also assert that corticosteroids are immunosuppressant drugs that may provide temporary relief of asthma symptoms but may lead to more serious chronic disease and to increased chances of death. Medical opinion is that this assertion is uninformed scare-mongering. The medical use of corticosteroids is not for symptom relief but to prevent inflammation that can have serious consequences. Inhaled corticosteroids, which do not spread through the body and cause widespread effects but stay on the breathing passages and prevent inflammation, are medically preferred to systemic corticosteroid therapy.

Most homeopaths believe that the fundamental causes of disease are internal and constitutional, and that infectious disease is not just the result of infection but also of susceptibility. This leads them to seek to avoid conventional treatments that suppress symptoms. Mainstream physicians accept that some disease is indeed a disturbance in normal function, whether due to external, genetic, or internal reasons. However, they consider that most disease can be attributed to a combination of external causes (such as viruses, bacteria, toxins, dietary deficiency, physical injury) and physiological dysfunction (including genetic defects and mutations such as those which trigger cancers), all of which homeopaths consider to be co-factors to disease, not causes of them. Conventional physicians often use drugs simply to suppress the symptoms of a disease (to alleviate the pain, injury, and distress that they cause). However, the main goal of medical treatment is to eliminate the causes of the disease with the help of drugs.

Whereas homeopaths emphasize that they provide remedies tailored to the individual patient's symptoms, conventional medicine focuses on treatments with demonstrable efficacy when given in a standard form to large populations of patients with a given disease. However, large clinical trials also seek to identify subgroups of patients (identifiable by age, gender, ethnicity, lifestyle, comorbidities etc.) that are "responders" or "non responders" to a new treatment, to provide a rational basis for individualization of treatments. Conventional physicians have access to a very large repertoire of prescription drugs for this purpose (11,706 in The U.S. Food and Drug Administration Approved Drug Products with Therapeutic Equivalence Evaluations 26th Edition Electronic Orange Book (EOB)4 ) , a repertoire that is constantly changing as less effective drugs are replaced by better drugs.

Medical organizations' attitudes towards homeopathy

The American Medical Association (AMA) was founded in 1847, three years after the American Institute of Homeopathy. From the 1860s to the early 20th century, the AMA's ethical code forbade its members to consult with fellow MDs who practiced homeopathy. Although the AMA did not enforce many of its ethical guidelines, the "consultation clause" was one of the few that it did. Today, the AMA is no longer overtly antagonistic to homeopathy, but their current policy statement says: "There is little evidence to confirm the safety or efficacy of most alternative therapies. Much of the information currently known about these therapies makes it clear that many have not been shown to be efficacious. ".

Safety and efficacy of homeopathy

In conventional medicine (see New Drug Application), the basic phases of evaluating a drug are determining if it causes dangerous effects in healthy volunteers, if it is adequately present in the body to achieve an effect, and if it is more effective than established treatments, against a disease.

In conventional medicine, randomized controlled trials rely on statistical analysis of large groups of patients all of whom are given the same treatment to determine whether that treatment is indeed effective. This conflicts with an approach that believes that treatments must be individually tailored to each patient. In reality, some homeopathic trials do use some standardization, but not always to an extent which would make the trials statistically robust.

Scientific basis of homeopathy

See articles on solitons, clathrates, nanobubbles and The memory of water.

Homeopathy was developed at a time when many important concepts of modern chemistry and biology, such as molecules and germs, were understood poorly if at all. In Hahnemann's day, many chemists believed that matter was infinitely divisible, so that it was meaningful to talk about dilution to any degree. Although the hypothesis of atoms can be traced back to the ancient Greeks, their size was not calculated until 1865 (by Josef Loschmidt).

We now know that, for example, a teaspoon of seawater (5 ml) contains about 160 mg of NaCl. The molecular weight of NaCl is 58.4, so by Avogadro's number, (or, in German-speaking countries, Loschmidt's number), 58.4 g of NaCl (one mole) contains 6.02×10²³ molecules. We can thus calculate that our teaspoon contains about 2×10²¹ molecules of NaCl. A 12C dilution of seawater will have about one molecule of NaCl per litre.

Thus homeopathic remedies diluted to more than about $12C$ are virtually certain to contain not even a single molecule of the initial substance. This is recognized by advocates of homeopathy, who assert that the essential healing power is not to be found in the chemical action of molecules, but perhaps in the arrangement of the water molecules, giving rise to the expression 'the memory of water'.

Water is not simply a collection of molecules of H₂O, it contains several molecular species including ortho and para water molecules, and water molecules with different isotopic compositions such as HDO and H₂¹⁸O. In addition, even double-distilled and deionized water always contains trace amounts of contaminating ions. There is some support for the notion that water can have properties that depend on how it has been processed (i.e. that water has, in some sense, a kind of "memory"). The evidence indicates that the "memory" is due primarily to solute and surface changes occurring during this processing. In particular, water, as a result of repeated vigorous shaking, might include redox molecules produced from water, dissolved atmospheric gases and airborne contaminants, silicates - tiny glass "chips", nanobubbles and their material surfaces, dissolved ions, including from the glassware, apart from the original medicinal substance it was diluting. It is theorized that each substance that is placed in the double-distilled water will interact with the silicate fragments in differing ways, thereby changing the structure of the water. There might also be some effects of successive shaking on water structure - "clustering" of water molecules.

These are not mechanisms of memory in any cognitive sense; the term memory here is used as a metaphor, implying only that the past history has a discernible influence on the present properties, but homeopaths believe that, through these or other mechanisms, water can form and retain some useable "memory" of the original medicinal substance. Many homeopathic remedies are however available as solid preparations -"pillules" of lactose and/or sucrose, intended as inert cores which are transformed into homeopathic drugs by impregnating them with a dilution of homeopathic stock

In brief, for homeopathy to receive serious scientific consideration, there needs to be plausible explanations for the following:

• how the process of manufacturing a homeopathic remedy could yield a biologically active substance or solution
• why the principle of similars might apply in the case of homeopathic remedies
• how a biological mechanism could have evolved to recognize the specific nature of homeopathic remedies

There also needs to be

• clear and irrefutable evidence for the efficacy of homeopathic remedies, evidence that cannot be explained by placebo effects

These stringent demands are often summarised by the maxim "Extraordinary claims require extraordinary proof".

While homeopaths also want to understand how their medicines work, they assert that there is a double standard in medicine and science because there is a long history of certain conventional medical treatments that have no known mechanism of action but that are regularly used; only relatively recently, for instance, has it been understood how aspirin works, but before then doctors used it regularly in spite of an inadequate understanding of its actual mechanism. Further, homeopaths assert that the overall body of evidence for homeopathy, including the body of clinical research, animal research, basic sciences research, historical usage of homeopathic medicines in the successful treatment of people in treating various infectious disease epidemics, and widespread and international usage of homeopathic medicines today, provide extraordinary evidence for the benefits of this system of nature medicine.

Some materials scientists, physicists, and other scientists have investigated how homeopathic medicines might work including some reports of the alteration of water by homeopathic preparations, but there are no generally accepted theories about how these occur or about how those altered properties could affect biological systems.

Tests of the efficacy of homeopathic remedies

Various reviews of double-blind and placebo controlled clinical research have shown that the effects of homeopathic medicines are different from and more beneficial than the effects of a placebo. A 1991 meta-analysis published in the BMJ (British Medical Journal) found that the placebo response is an inadequate explanation for the positive responses that controlled trials have found, This review of research assessed 105 trials, 81 of them positive. The authors concluded: “Based on this evidence we would be ready to accept that homoeopathy can be efficacious, if only the mechanism of action were more plausible”, “the evidence presented in this review would probably be sufficient for establishing homeopathy as a regular treatment for certain indications”, and "the evidence of clinical trials is positive but not sufficient to draw definite conclusions". Linde and colleagues analysed 89 trials and found a mean odds ratio of 2.45 (95% confidence interval, 2.05–2.93), in favor of homeopathy. When considering just those trials of “high quality” and after correcting for publication bias, the findings actually remained statistically significant (means odds ratio of 1.86). The main conclusion was that the results “were not compatible with the hypothesis that the effects of homoeopathy are completely due to placebo.” The authors later analyzed these trials and concluded that higher quality trials were less likely to be positive than those of lower quality, though they acknowledged that this is true of conventional medical research too, saying in the first sentence of the article, “There is increasing evidence that more rigorous trials tend to yield less optimistic results than trials with less precautions against bias.”

Several meta-analyses evaluating the homeopathic treatment of specific diseases has also found positive results, including the treatment of childhood diarhea, influenza, certain post-surgical conditions and respiratory allergies

However, there are also several meta-analyses that have suggested that the effect from a homeopathic medicine was no better than a placebo

A controversial comparison of homeopathic and conventional medical studies was published in the Lancet. This study compared 110 placebo-controlled homeopathic trials with a “matched” 110 conventional medical trials. The researchers found that only 21 homeopathic trials were “high quality” according to their standards, while only 9 conventional medical trials were of a similar “high quality.” The researchers then chose to compare only those larger trials of this high quality subset, and they determined that the results of the 8 remaining homeopathic trials and the 6 remaining conventional medical trials showed that homeopathic treatment was comparable with a placebo, while the conventional medical trials were not comparable with a placebo effect.

Two newer analyses of the Shang research assert that its conclusions are “less definite” than they have been previously presented. The new analyses note that Shang omitted several high quality studies in homeopathy, that Shang’s definition of “high quality” is open to question (initially, the authors didn’t report which studies were defined as “high quality,” and today, there is no clarity on the point score for each study; several studies by Reilly, for instance, should have been defined as high quality according to the published standards but were not). Further, the new analyses note that Shang never evaluated or compared all of the “high quality” studies but only the “larger” studies and both papers note that there was a statistically significant difference between results from homeopathic treatment vs. placebo (P=0.039; odds ratio = 0.76).

There have been many published trials of specific homeopathic remedies; they are mostly small and, according to critics, flawed in design (for example, lacking randomisation, blinding, objective outcome measures or adequate controls), in analysis or in interpretation. Many of these have indicated positive effects, but generally, trials that are larger and more rigorous have tended to show little or no statistically significant effects. Some studies of homeopathy have been funded by the U.S. National Center for Complementary and Alternative Medicine (NCCAM).

The Cochrane Collaboration is an organisation that publishes meta-analyses of trial results; most of their analyses of homeopathic treatments indicate no significant benefit. The most supportive of their analyses is of the possible benefits of Oscillococcinum for influenza and influenza-like syndromes. This was a meta-analysis of seven randomized controlled trials, three prevention trials (number of participants, $N=2265$) and four treatment trials, $(N=1194)$. Overall, the authors found no evidence of any benefits in preventing influenza, but some evidence of a small effect on the duration of symptoms. The outcome was sufficiently promising that further trials were recommended, but not strong enough for the remedy to be recommended for first-line therapy.

Homeopaths often consider large trials invalid because they do not reflect the individualized nature of homeopathic treatment. They consider that their direct clinical experience of the effects of their remedies on their patients, and the satisfaction reported by their patients in surveys, is sufficient evidence of efficacy. They consider that the critical response of scientists and conventional medicine to the published evidence supportive of homeopathy reflects prejudice against homeopaths, and they believe that these attitudes lead to the suppression of evidence supportive of homeopathy.

Safety

The highest ideal of cure is the speedy, gentle, and enduring restoration of health by the most trustworthy and least harmful way (Samuel Hahnemann)

The U.S. Food and Drug Administration's view of homeopathy is that there is no real concern about the safety of most homeopathic products because of the extremely small dosages. The F.D.A. has deemed that the vast majority of homeopathic medicines are over-the-counter drugs (OTC), that is, drugs that do not need a doctor's prescription and that are safe enough for home care. In the U.S.A., homeopathic remedies must have at least one indication for usage for a disease or condition that is self-limiting and that does not require medical diagnosis or medical monitoring. The European Union allows homeopathic medicinal products, if they are at least 3X, that is, they may not contain either more than one part per 10 000 of the mother tincture or more than 1/100th of the smallest dose of an active substance. No specific therapeutic indication may be given on the label of the product. Some physicians, however, maintain that homeopathic treatment is relatively unsafe, because it might delay conventional medical treatment. Homeopaths respond to these concerns by noting that using homeopathic medicines can delay or reduce the use of conventional medicines that are ineffective and dangerous.

Probably every modern pharmacologist would agree with Hahnemann that the drugs prescribed by conventional physicians of the 19th century were at best ineffective and often dangerous. However, some homeopaths question whether even modern medical drugs are safe and effective, and recommend homeopathic remedies instead. For example, a 2006 survey by the U.K. charitable trust 'Sense About Science' revealed that homeopaths were advising travelers against taking conventional anti-malarial drugs, instead recommending they take a homeopathic remedy. Even the director of the The Royal London Homeopathic Hospital condemned this:

I'm very angry about it because people are going to get malaria - there is absolutely no reason to think that homeopathy works to prevent malaria and you won't find that in any textbook or journal of homeopathy so people will get malaria, people may even die of malaria if they follow this advice.

Another concern of conventional physicians is that some homeopaths discourage the use of vaccines. Many homeopaths think that vaccination for common diseases, such as measles and chicken-pox, is unnecessary, and some believe that vaccines can even be damaging to health, because of the mercury and aluminum in them, because the bacterium or virus in the vaccine may neither be dead nor weak enough, and/or because some childhood infectious diseases may strengthen immune responsiveness. Such advice is considered irresponsible by many public health professionals, who assess the benefits of vaccination as vastly outweighing the risks. (see reference for explanation of the risks associated with measles and chicken-pox).

Overview

Many people, including many mainstream scientists and physicians, are fascinated by homeopathy for many different reasons. Homeopathy has a rich history, and is an important element in the history of medicine generally. The growth of homeopathy in the 19th century had a significant influence in determining how conventional medicine organised and developed, and in how it came to formulate its present vision of evidence-based medicine, in contrast to practise based on individual clinical experience.

Homeopaths are proud of their history, and are convinced of the efficacy of their remedies based mainly on their clinical experience, bolstered by the outcomes of the majority of clinical trials. Homeopathic remedies are used by many people throughout the world; like many other complementary and alternative therapies, homeopathy generally scores very highly in "patient satisfaction" surveys, and it has a reservoir of public support. In the U.K. for instance, one of the countries where homeopathy has relatively strong public support, a survey cited by the British Homeopathic Association found that 15% of the public "trust" homeopathy.

Mainstream scientists and medical professionals are also often interested in homeopathy, despite generally being dismissive of the theories and of the claims for efficacy. They are interested in why so many people believe in homeopathy, when they consider that it has no plausibility. They are interested too in why some studies appear to have positive outcomes - do these reflect real efficacy, or can they be accounted for by flaws in study design or in statistical analysis, or "publication bias" - the tendency for small studies with chance positive outcomes to be published while studies with negative or inconclusive outcomes are not. They also are interested in whether positive results against expectation sometimes reflect manipulation of data or perhaps even fraud.

This interest has a much broader relevance than homeopathy. A huge number of research papers are published every year in the scientific literature - PubMed covers more than 6,000 journals in biology and medicine, and excludes very many journals that do not meet its quality criteria. Many of these papers report results that turn out to be wrong for many different reasons. Usually, errors are exposed when attempts to replicate the data fail; often contradictory results are reported, but often papers are quietly "forgotten" - never cited because their flaws become evident. Sometimes in conventional science overt fraud is revealed, but often it is impossible to confirm that fraud is present. But in conventional science generally, what counts is replicability - it doesn't matter whether unreliable results are the result of fraud or error, individual reputations depend ultimately on publishing important data that can be replicated consistently. Accordingly, scientists are professionally concerned with understanding the sources of error - including all sources of error, in study design, methodology, analysis and interpretation; and for some of them, homeopathy seems like a source of examples where they feel that the conclusions "must" be wrong, so finding the sources of error can teach important lessons.

Of course, it is possible that mainstream scientists and physicians have it wrong; perhaps homeopathy is indeed effective, and, if so, there is something important to be studied. Mainstream scientists enjoy a considerable degree of trust, and their assertions are often accorded considerable "authority". Some may exploit this authority, but the ethos of science generally is one of disciplined skepticism - including skepticism about all that we think we know. Scientific theories are never proven, but always provisional, subject to revision and occasional abandonment as knowledge grows. So scientists generally reject arguments from authority as being of any value - only arguments from reason, embracing current knowledge and understanding count, and these are arguments that each scientist must make for himself or herself, and make afresh as fresh knowledge comes.

Scientists in almost any area expect that, what today is the consensus understanding will, in some tomorrow, by a mere curiosity in the history of science. They do not have all the answers, and they expect that many of their present "answers" will turn out to be not quite right and some will be quite wrong. They generally think it very unlikely homeopathy will ultimately prove to have any validity; but of course this is one of those things that they might turn out to be wrong about.